nervous system

Question 1

three types of nerve tissue

Answer 1

neurons
synapse
neuroglial cells

Question 2

function of neurons

Answer 2

carryout chemical/electrical reactions
most transmit/receive signals (some only one)
only in one direction

Question 3

structure of neurons (4)

Answer 3

cell body
dendrites
axons
terminal

Question 4

names for cell body

hint- surrounding the crayon

Answer 4

soma

perikaryon

Question 5

three traits of dendrites

Answer 5

short highly branched
possibly many near cell body
message receivers- incoming (dentritic spines)

Question 6

4 traits of axons

Answer 6

1 long branch
transmitter of signal
axonal hillock (funnel) connects to cell body
node of Ranvier: space between neuroglial cells

Question 7

two traits of terminal

Answer 7

distal end of nerve cell

transmits signal to the next cell

Question 8

what is synapse

Answer 8

junction between two neurons

Question 9

two parts ? of synapse

Answer 9

neurotransmitter

neuroglial cells

Question 10

3 things about neurotransmitters

Answer 10

chemical released by nerve
1 to 3 kinds (30 different types)
synthesized in nerve cell (knobs) and stored in vesicles

Question 11

ex. of neurotransmitters

Answer 11

ex. acetylcholine: activates skeletal muscles

Question 12

what are neuroglial cells

Answer 12

accessory cells
helper cells?
lots more than nerve cells

Question 13

4 functions of neuroglial cells

Answer 13

insulation
fill spaces
protect
remove neurotransmitter

Question 14

list three membrane potentials

Answer 14

resting potential
action potential
repolarization ?

Question 15

what are nodes of Ranvier

Answer 15

area between neuroglial cells

Question 16

describe 4 things about nodes of ranvier

Answer 16

points of ion exchange
charge only forms at the nodes

 potential appears to jump from node to node

speed correlated to diameter of nerve (faster/greater)

Question 17

another name for impulse conduction

hint- think of mandatory salt

Answer 17

saltatory conduction

Question 18

what about neuroglial cells wrapping around the axon?

is this related to impulse conduction?

Answer 18

they provide insulation

Question 19

is resting potential polarized or depolarized?

Answer 19

polarized

Question 20

what is resting potential

Answer 20

charge difference between outside and inside of cell when not active

Question 21

why do cells have resting potential?

Answer 21

due to the movement of Na+ and K+

Question 22

what are corresponding negative charges to resting potential (3)?

Answer 22

Cl-
PO4 -3
SO4 -2

Question 23

2 traits about the sodium/potassium cation pump

Answer 23

Na+ pumps three sodium out for every 2 in

K+ are pumped inward?

Question 24

what does the K+ channel (pore) do?

Answer 24

allows diffusion of K+ outward

Question 25

how does diffusion assists the K+ channel?

Answer 25

Diffusion = electrostatic attraction + electrostatic repulsion
(+) (-) (+) (+)

	net result:  more positives leave the cell than enter 
		positive charge builds up outside / negative inside (-70 mv)

Question 26

is action potetial polarized or depolarized?

Answer 26

depolarized

Question 27

describe action potential

Answer 27

when signal is to be sent

Question 28

what happens when Na+ gate is triggered to open?

Answer 28

Na+ flows into cell within 1 millisecond

Question 29

what’s result of action potential in terms of charge?

Answer 29

there’s an inverse of charge- negative outside and positive inside
equaling +30 mV

Question 30

which forces drive Na back into the cell? (3)

Answer 30

Diffusion
Electrostatic attraction
Elecrtrostatic repulsion
(forces are additive)

Question 31

what is threshold?

Answer 31

minimum signal needed to activate action

Question 32

another name/phrase for threshold

Answer 32

meet or beat

Question 33

what is the all-or-none response?

Answer 33

the neurons fire or not- no intermediates

Question 34

what is purpose of repolarization

Answer 34

 re-establish proper ions and charge to return to resting potential

Question 35

what are the three steps in repolarization?

Answer 35

Na+ gate is closed
Na+/K+ pump pumps out the Na+ and pumps in the K+
K+ channel(pore) allows the K+ out